Added SharedData

Author: PaulNonatomic

CHANGELOG.md

@@ -1,10 +1,15 @@
 # Change Log
 
+## [0.8.0-beta] - Aug 25, 2024
+- Added support for shared data between states. The SharedData object is a generic data store.
+  - States can access shared data via `this.SharedData`
+- Shared data is exposed externally to the statemachine via StateMachineController.SharedData.
+
 ## [0.7.2-beta] - Aug 24, 2024
 - Exposed the JumpTo method on the StateMachineController
   - This allows users to manually trigger a JumpIn node externally broadening the use-cases for the VSM
 - Exposed the State member of the StateMachine through a public State member of the StateMachineController
-  - This allows users to determine the current state and to directly call methods upon externally.
+  - This allows users to determine the current state and to directly call methods upon it externally.
   - I experimented with implementing a StatePattern with all States implementing a common interface.
 
 ## [0.7.1-beta] - Aug 21, 2024

README.md

@@ -81,6 +81,46 @@ The State Machine Editor supports copy and paste within and between state machin
 
 https://github.com/user-attachments/assets/09c1b644-c519-4bfd-8c29-4b0771d8d8b6
 
+## Shared Data
+States have access to a shared data store
+
+```cs
+public class StateOne : State
+{
+    [Transition] public event Action OnComplete;
+
+    public override void OnEnterState()
+    {
+        SharedData.SetData("age", 42);
+        OnComplete?.Invoke();
+    }
+
+    public override void OnExitState()
+    {
+        //...
+    }
+}
+    
+public class StateTwo : State
+{
+    [Transition] public event Action OnComplete;
+    
+    public override void OnEnterState()
+    {
+        var age = SharedData.GetData<int>("age");
+        Debug.Log($"StateTwo - Age:{age}");
+        
+        OnComplete?.Invoke();
+    }
+
+    public override void OnExitState()
+    {
+        //...
+    }
+}
+```
+
+This same data store is exposed externally to the state machine through the StateMachineController.SharedData
 
 ## License
 VisualStateMachineV2 is licensed under the MIT license

Runtime/Data.meta

@@ -0,0 +1,75 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+
+namespace Nonatomic.VSM2.Data
+{
+	public interface ISharedData
+	{
+		event Action<string, object> OnDataChanged;
+		event Action OnDataCleared;
+		
+		T GetData<T>(string key);
+		void SetData<T>(string key, T value);
+		void ClearData();
+	}
+	
+	public class SharedData : ISharedData
+	{
+		public event Action<string, object> OnDataChanged;
+		public event Action OnDataCleared;
+		
+		private readonly Dictionary<string, object> _data = new Dictionary<string, object>();
+		private readonly ReaderWriterLockSlim _lock = new ReaderWriterLockSlim();
+
+		public T GetData<T>(string key)
+		{
+			_lock.EnterReadLock();
+			
+			try
+			{
+				if (!_data.TryGetValue(key, out var value)) return default;
+				
+				if (value is T tValue)
+				{
+					return tValue;
+				}
+				
+				throw new InvalidOperationException($"Attempted to retrieve type {typeof(T)} but data is of type {value.GetType()}");
+			}
+			finally
+			{
+				_lock.ExitReadLock();
+			}
+		}
+
+		public void SetData<T>(string key, T value)
+		{
+			_lock.EnterWriteLock();
+			
+			try
+			{
+				_data[key] = value;
+				OnDataChanged?.Invoke(key, value);
+			}
+			finally
+			{
+				_lock.ExitWriteLock();
+			}
+		}
+		
+		public void ClearData()
+		{
+			_lock.EnterWriteLock();
+			try
+			{
+				_data.Clear();
+				OnDataCleared?.Invoke();
+			}
+			finally
+			{
+				_lock.ExitWriteLock();
+			}
+		}
+	}
+}

Runtime/Data/SharedData.cs

@@ -1,5 +1,6 @@
 #pragma warning disable 0067
 
+using Nonatomic.VSM2.Data;
 using Nonatomic.VSM2.StateGraph.Attributes;
 using UnityEngine;
 
@@ -10,7 +11,8 @@ public abstract class State : ScriptableObject
 	{
 		public GameObject GameObject { get; set; }
 		public StateMachine StateMachine { get; set; }
-		
+		public ISharedData SharedData { get; set; }
+
 		public abstract void OnEnterState();
 		public abstract void OnExitState();
 

Runtime/Data/SharedData.cs.meta

@@ -4,6 +4,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using JetBrains.Annotations;
+using Nonatomic.VSM2.Data;
 using Nonatomic.VSM2.Logging;
 using Nonatomic.VSM2.NodeGraph;
 using Nonatomic.VSM2.StateGraph.States;
@@ -14,7 +15,9 @@ namespace Nonatomic.VSM2.StateGraph
 	public class StateMachine
 	{
 		public event Action<State, StateMachineModel> OnComplete;
-		
+
+		public ISharedData SharedData { get; }
+
 		public State State => _currentNode?.State;
 		public StateMachineModel Model { get; private set; }
 		public bool IsComplete { get; private set; }
@@ -24,14 +27,17 @@ public class StateMachine
 		private Dictionary<string, List<StateTransitionModel>> _transitionLookup = new();
 		private Dictionary<JumpId, StateNodeModel> _jumpNodeLookup = new();
 		private CancellationTokenSource _cancellationTokenSource = new();
-		
+
 		public StateMachine(StateMachineModel model, GameObject gameObject)
 		{
-			Model = StateMachineModel.CreateInstance(model);
-			Model.Initialize(gameObject, this);
-
-			CreateNodeLookupTable();
-			CreateTransitionLookupTable();
+			SharedData = new SharedData();
+			Initialize(model, gameObject);
+		}
+		
+		public StateMachine(StateMachineModel model, GameObject gameObject, ISharedData sharedData = null)
+		{
+			SharedData = sharedData ?? new SharedData();
+			Initialize(model, gameObject);
 		}
 
 		public void Update()
@@ -80,7 +86,7 @@ public void Exit()
 			_currentNode.Exit();
 			IsComplete = true;
 		}
-		
+
 		public void JumpTo(JumpId jumpId)
 		{
 			if (!_jumpNodeLookup.TryGetValue(jumpId, out var nextNode))
@@ -113,6 +119,15 @@ public void OnDestroy()
 			Model = null;
 		}
 
+		private void Initialize(StateMachineModel model, GameObject gameObject)
+		{
+			Model = StateMachineModel.CreateInstance(model);
+			Model.Initialize(gameObject, this, SharedData);
+
+			CreateNodeLookupTable();
+			CreateTransitionLookupTable();
+		}
+
 		private void CreateTransitionLookupTable()
 		{
 			_transitionLookup.Clear();
@@ -127,7 +142,7 @@ private void CreateTransitionLookupTable()
 				_transitionLookup[transition.OriginNodeId].Add(transition);
 			}
 		}
-		
+
 		private void CreateNodeLookupTable()
 		{
 			_nodeLookup.Clear();

Runtime/StateGraph/State.cs

@@ -1,4 +1,5 @@
 using System;
+using Nonatomic.VSM2.Data;
 using Nonatomic.VSM2.StateGraph.States;
 using UnityEngine;
 
@@ -15,6 +16,7 @@ public class StateMachineController : MonoBehaviour
 		public string Id => _id;
 
 		public State State => _stateMachine?.State;
+		public ISharedData SharedData => _stateMachine.SharedData;
 
 		/// <summary>
 		/// Gets the current StateMachineModel, either from the active state machine or the serialized field.

Runtime/StateGraph/StateMachine.cs

@@ -1,4 +1,5 @@
 using System.Linq;
+using Nonatomic.VSM2.Data;
 using Nonatomic.VSM2.Logging;
 using Nonatomic.VSM2.NodeGraph;
 using Nonatomic.VSM2.Utils;
@@ -178,7 +179,7 @@ private void ValidateNodes()
 			}
 		}
 
-		public void Initialize(GameObject gameObject, StateMachine stateMachine)
+		public void Initialize(GameObject gameObject, StateMachine stateMachine, ISharedData sharedData)
 		{
 			if (!gameObject || stateMachine == null) return;
 
@@ -191,6 +192,7 @@ public void Initialize(GameObject gameObject, StateMachine stateMachine)
 
 				instantiatedState.GameObject = gameObject;
 				instantiatedState.StateMachine = stateMachine;
+				instantiatedState.SharedData = sharedData;
 				stateNode.State = instantiatedState;
 				stateNode.Awake();
 			}

Runtime/StateGraph/StateMachineController.cs

@@ -78,7 +78,7 @@ protected virtual void CreateStateMachines()
 			{
 				if (model == null) continue;
 
-				var subSubStateMachine = new StateMachine(model, this.GameObject);
+				var subSubStateMachine = new StateMachine(model, GameObject, SharedData);
 				subSubStateMachine.SetParent(StateMachine);
 				SubStateMachines.Add(subSubStateMachine);
 			}